Have you checked the muffler spark arrester for clogging?
As above typically is just a blocked muffler, however could be a few things..
Didn't think to check, as it ran, and it seemed the exhaust was functioning. I'll take it off and give it a good clean. Should I just clean the arrester, or try clean all the inside of the muffler ?
From stihl themselves the proper way to check the carburettor is to pressure test it, mainly by pressurising the fuel inlet line and making sure it holds. Have you put a kit in it?
I haven't. Did consider picking one up years back, but forgot about it. I think I saw one that supposedly does vacuum testing, and pressure testing, on ebay, will have to have a look.
There are a few circuits in the carb that you can't check or clean without removing welsh plugs, but carb issues like that are usually only a problem if it hasn't run in a long time
Without knowing the condition of the carb, would it be worth removing the welsh plugs, and cleaning, and replacing them, or not worth it ?
Also check the fuel lines and filter, a tiny hole in the fuel line or blocked filter will do exactly this
One suggestion before go any further is to replace the fuel filter in the tank and test again.
I had a look at the filter, it looked really clean, almost new. I'll take a pic and post, but in the meantime, before buying a new one, would it be worth taking it out, cleaning with parts cleaner, and maybe pushing a little air through it to see if it isn't blocked ?
Not sure why you tried it with the screws all the way in? that will stop all fuel from going through the carburettor. 1 1/2 turns out is usually where i would start
Sorry, I meant all the way in to a minimum, but not fully closed. This is the video I followed when I did it..https://www.youtube.com/watch?v=gmhxTvGRtCg
A compression test won't tell you very much other than if the rings are ok, and I am assuming you have done the visual check through the exhaust port..
A mate ok mine had terrible problems with a Stihl chainsaw, he pulled the carby apart several times before taking it to a Stihl shop. They knew straight away what the problem was it had a pinhole in the carby feed line and said it was a common problem with them. To me that plug looks super lean so could be the fuel supply problem
Would that only affect fuel delivery at lower RPMs ? When I hold down the accelerator trigger to max revs, doesn't seem to cut out.
Thanks for all the feedback
Q: Is there any difference in using a parts cleaner vs using a specific carburettor cleaner ?
This is what I use, https://www.supercheapauto.com.au/p/sca-sca-brake-and-parts-cleaner---400g/0240.html#vid=EpzUqZuHNVTOR1UXVpMMXA%3D%3D&q=parts+cleaner&lang=en_AU&start=6
Should I be using something like this
https://www.supercheapauto.com.au/p/sca-sca-throttle-body-and-carby-cleaner---400g/0238.html ?
Thanks again.
